Black Box, (Service Number - BBX-8995-1)[1] or BB for short, was a "Smart"AI construct built by ONI to accompany the ex-Spartan, CaptainSerin Osman on her mission to sow discord throughout the remaining Sangheili population after the Great Schism.[2] His donor was Doctor Graham J. Alban, a neurosurgeon and psychologist who had worked for the SPARTAN-II Program. Doctor Alban considered his actions more reprehensible than that of the actions of Catherine Halsey due to him believing that she was devoid of morality. This later lead to him taking his life due to his guilt from his actions. When he took his life however, he made sure to do it in such a way so that his brain could stay intact so he asked for his brain to be made into an A.I. to watch over the remaining SPARTANS.[3]

Unlike most AIs, both smart and dumb, BB felt that there was no point in masquerading as a human avatar. He considered himself as "pure intellect," choosing to be seen as a featureless box.[4]

As with other smart AI's, BB was capable and also tasked with running the operations of the UNSC Port Stanley. He was capable of controlling the entire ship without the need for a human interaction.[5]

BB had the opinion that it is not a good idea to get too invested in humans, fearing that he may "end up like Cortana" and as such in his early days held a very formal, sometimes verging on cynical relationship with the crew members of the Port Stanley.[6]

Other than Cortana, Black Box was the only other A.I. known to have interfaced with a Spartan through the Neural pathways found in their armor. He teamed up with Naomi-010 to assist on the raid of the Piety.

On more than one occasion, Black Box showed that he was willing to be as ruthless as necessary to fulfill the mission. At one point after rescuing "Mr. Muir," the last survivor of a glassedworld, Black Box prepared to jettison Muir into space purely on the basis of "asking too many questions." He referred to the procedure as "Airlock Diplomacy" and was only dissuaded when Osman intervenes.

Black Box was planning on persuading Dr. Phillips to donate his brain to the AI program before his death.

He made a comment that seems to suggest that the MA5B is of less quality then the MA5C.

Although this A.I.'s name is Black Box, his holographic avatar is blue. It is impossible for a hologram to be black because black is a result of the displacement of light. Dark blue is the closest substitute.